Well circulation tool

ABSTRACT

A tool for use with a well string to improve circulation of fluid pumped to a well hole. The tubular body section of the tool has a channel for fluid which extends through the side wall to the outside. Inside the body section there is a previously set operable member which covers over the channel and thus blocks the flow of fluid and which can be operated by an action taken at the surface to uncover the channel and permit flow of fluid from the tool into the well hole. Among other uses, the tool can be employed to restore adequate circulation to a bore hole when a bit plugs, or to increase and/or control circulation during the drilling, fishing, or servicing of a hole.

United States Patent Oliver Mar. 26, 1974 [5 WELL CIRCULATION TOOL2,312,789 3/1943 Appleby 175/317 x 2,765,146 10/1956 Williams... 175/317[751 Inventor: Housmn 2,882,020 4/1959 Carr et al.... 175/237 [73]Assignee: Cities Service Oil Company, Tulsa, 3,552,412 1/1971 Hagar eta1. 175/231 UX Okla. Primary Examiner-Dav1d H. Brown P116111 Allg- 1972Attorney, Agent, or Firm-Elton F. Gunn 211 Appl. No.: 285,145

[57] ABSTRACT A tool for use with a well string to improve circulation2? i 175/237 175/3 5 1734 of fluid pumped to a well hole. The tubularbody sec- 'f 23 tion of the tool has a channel for fluid which extends I1 o .earc 6 through the side wall to the outside. Inside the bodysection there is a previously set operable member 56 R f 1 d whichcovers over the channel and thus blocks the 1 e erences flow of fluidand which can be operated by an action UNlTEYD STATES PATENTS taken atthe surface to uncover the channel and per- 2,128,352 8/1938 Creighton175/318 X mit flow of fluid from the tool into the well hole. .83 952 ms/3l8 X Among other uses, the tool can be employed to re- 2,828,1073/1958 Hobo 175/237 store adequate circulation to a bore hole when a bitppi plugs, or to increase and/or control circulation during 0r ary....2,046,798 7/1936 Thrift 175/318 x dnnmg fishmg or semcmg of a hole2,312,018 2/1943 Beckman 175/237 X 13 Claims, 5 Drawing Figures Drillingfluid Drilling fluid WELL CIRCULATION TOOL BACKGROUND OF THE INVENTIONIn either drilling or fishing operations it is conventional practice tocirculate a fluid such as drilling mud in the bore hole to cool thedrill bit, flush away drill cuttings, and lubricate the string as itruns in the hole. This is accomplished by pumping the fluid down thedrill string and out of discharge orifices in the drilling bit. Shouldthe orifices of the bit become even partially plugged, adequatecirculation of fluid to the hole can be lost. As a consequence, thebeneficial functions of fluid circulation are also lost or elseseriously impaired. Plugging of the bit can also be dangerous,especially in the event of an unexpected pressure kick which occurs whena high pressure zone is penetrated, or when attempting to kill a kickwhich has already occurred, since the ability to control pressure at thebottom of the hole is lost if pumping of drilling fluid cannot beadequately maintained.

Full or partial plugging of the bit, with concomitant impariment or lossof circulation, can also occur during fishing operations wherein junk ordebris must be cleared from the hole before drilling can be effectivelycontinued.

Prior methods of restoring adequate circulation of drilling fluid afterplugging of the bit include making a round trip to replace the bit andperforating the drilling string about the bit by shooting. Since it isnot practical to trip the string out of the hole upon encountering akick, it has been necessary to perforate the string while it remains inthe hole, but this requires preparation and lowering of a shot. Valuabletime is consumed in an emergency situation and affords little controlover the degree of perforation and, hence, the resulting pressure whichwill be required to restore adequate circulation. As a consequence, aneed was recognized for a method for restoring adequate circulationofdrilling fluid to a well hole after plugging of the bit, and preferably,to restore adequate circulation without substantial increase or decreasein the pumping pressure required.

SUMMARY OF THE INVENTION It is therefore an object of this invention tomaintain or improve circulation of fluid to a well hole during drillingor servicing of a well.

Another object of this invention is to provide a method for quicklyrestoring adequate circulation of drilling fluid to a bore hole afterthe drilling bit has become plugged.

Still another object is to maintain or increase the rate at whichdrilling fluid is pumped to a bore hole without substantial increase ordecrease in the pressure required to achieve the circulation.

Even another object is to improve safety of the drilling operation whena kick is encountered.

Other objects and advantages of the invention will become apparent fromthe following description and the appended claims.

The present invention is a drilling tool which can be used incombination with other members of a drilling string to restore, improve,or enable control over circulation of fluid being pumped to the wellhole. The tool comprises a tubular body section having threads at eachend which are connectible to members of a well drilling string. Alongitudinal passageway extends through the body section for conveyingfluid received from the string. At least one channel extends through theside wall of the body section of the tool from the passageway therein tothe outside. There is a previously set operable member inside the bodysection which normally covers the channel through the wall, and whichuncovers the channel when operated. The purpose of the preexisting butnormally covered channel in the wall of the tool body is to provide aduct through which fluid being pumped can be diverted to the well holein the event that greater or improved circulation is needed which cannotbe accomplished by pumping through an attached drill bit or the like, orin the event that adequate circulation cannot be maintained due topartial or total plugging of a drilling bit. For instance, a plugged bitcan be by-passed by diverting fluid from the drilling string to the wellhole through the uncovered channel; or, the flow of fluid to the wellhole can be increased while still pumping fluid through an unpluggedbit. One or more preexisting channels can be used and all can be keptcovered when there is no need for restoring or improving circulation ofthe fluid, and uncovered by an action taken at the surface when a needfor improving or restoring circulation arises.

In addition to the channels and the operable member for the covering anduncovering thereof, the passageway in the body section of the tool canbe provided with a seat having a sealing surface which receives amatching sealing surface of a flow obstructing member emplaced in thepassageway. Accordingly, flow of fluid through the passageway beyond theone or more uncovered channels can be shut off, thus preventing flow ofthe fluid beyond the tool and thus diverting all of the fluid throughthe one or more channels in the wall of the body section. Means can alsobe employed for covering the channels again with the operable memberafter they have been uncovered, and for unseating the flow obstructingmember in the passageway should it again become desirable to pump all orpart of the fluid beyond the tool.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view, partly insection, of one embodiment of the tool of the present invention.

FIG. 2 is a side view of a weighted dart, or plunger, which can be usedto operate a slidable sleeve which covers the channels in the wall ofthe body section of the tool, and also to obstruct flow of fluid beyondthe tool.

FIG. 3 is a side view, partly in section, of a slidable sleeve which canbe used as the preset operable member in the tool of FIG. 1 for coveringand uncovering the channels in the wall of the body section of the tool.

FIG. 4 is a partially fragmentary and partially sectional side view ofanother embodiment of the invention wherein the sleeve arrangement andthe method of operating the sleeve are different from that shown in FIG.ll.

- FIG. S is a sectional view of slidable sleeve as in FIGS. 1 and 3which is held in position by means of a tensioned spring.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIG. 1, the tool isgenerally represented at l, and is connected by threads to a drill pipe2 and a drill bit 3. The tool is thus made up with the drilling stringat the time the bit is to be lowered in the hole, and does not performany special function until there is need to restore or improvecirculation of fluid being pumped through the string. The tubular bodysection 4 of the tool is attached at the upper end to a coupling 5 on adrill pipe, and the rotary bit 3 is screwed into the lower end of thebody section. A passageway 6 for drilling fluid runs through the bodysection 4 and interconnects at the upper and lower ends with fluidpassageways 6a and 6b which lead, respectively, from the drill string 2and into the drilling bit 3.

Channels 7 are drilled ducts which extend through the wall 8 of the bodysection from the passageway 6 to the outside. When the string is loweredinto the bore hole these channels are normally covered over by animpervious slidable sleeve 9 axially aligned and frictionally held inplace in the passageway 6 by means of O-rings 10 attached to the sleevein recessed grooves. As drilling or fishing, for instance proceeds withan unplugged bit, drilling fluid passes through the central passageway60 of the sleeve which is aligned with the other passageways 6, 6a and6b, thus maintaining a flow of drilling fluid to the bit since thechannels 7 are blocked off by the sleeve which has been preset inposition over the openings of the channels.

In FIG. 1, the sleeve 9 is thus shown in the preset position whereby thechannels 7 are covered over. The passageway 6 in the vicinity of thesleeve is recessed for a distance in excess of the sleeve length topermit the sliding thereof when operated and to provide a chamber whichaccomodates the thickness of the sleeve wall, the latter feature tendingto preserve the diameter of the fluid passageway 6 while also forming ashoulder 11 l at the top of the chamber which serves as an upper stopfor the sleeve. The upper edge3a of the drill bit 3 serves as a lowerstop for the sleeve.

Should the drill bit become wholly or partially plugged, circulation ofdrilling fluid to the well hole is adequately restored by uncoveringchannels 7 in order to divert flow from the bit and into the holethrough the wall 8 of the body section. This can be accomplished invarious ways, and two apparatus arrangements intended-for this purposeare shown in the drawings. FIGS. 1-3 illustrate use of a weighted dart,or plunger, which is dropped into the drilling string for displacing thesleeve downwardly to uncover the channels 7, and FIG. 4 illustrates useof a sleeve which normally covers the channels 7 when the sleeve isbottomed, and which can be lifted by wire line to uncover the channels.

Referring to FIGS. 1-3, the dart 12 is dropped into the drilling stringfrom the surface when circulation of drilling fluid must be restored orimproved, e. g. following partial or total plugging of the bit. AS soonas the dart is dropped, pressurization of the drilling fluid can beresumed. The momentum of the falling dart may in itself be sufficient todrive the sleeve downward below the channels 7, but in any event bothdart and sleeve are constructed so as to form a piston which can bedriven downward by pumping pressure when engaged as shown in thedrawing.

More specifically, the sleeve 9 comprises an attached or integral ring13 which projects into the central passageway and is axially alignedtherewith. With the sleeve shown, the ring is machine beveled to providean upper tapered sealing surface 13b. The upper part of the dart 12 isprovided with a matched bevel 14, so that when the dart and the sleeveare engaged as in FIG. 1, flow of fluid past the sleeve is effectivelyobstructed. Therefore, elevation of pumping pressure in the drillingfluid will displace the dart and sleeve downwardly and thus uncover thechannels 7 when dart and sleeve are mated as in FIG. 1.

FIG. 4 illustrates a different arrangement wherein the sleeve isnormally bottomed against the lower stop 22a for covering of thechannels 7. When there is a need to improve or restore fluid circulationto the well hole, a wire line tool is lowered which engages a latch 15on a rod 16 which extends inside the sleeve from one side to the other.The sleeve is then raised against the upper stop 11 by means of a wireline tool. A snap ring 17 which extends around the sleeve and isattached thereto in a groove engages a latching groove 18 in the wall ofthe passageway and thus holds the sleeve in an elevated position. Thewire line is then pulled loose from the sleeve and the latter remains inplace by engagement of the snap ring with the latching groove.

Should it become desirable to again cover up channels 7 once the sleevehas been shifted to uncover them, e. g. when a need is recognized tocirculate more fluid at a point below the tool, the sleeve can berelocated over the channels by an action taken at the surface. Whenusing a sleeve and dart arrangement as shown in FIGS. 1-3, the lowerspindle 19 of the dart is provided with a snap ring 20 attached theretoin a groove so that upon entry of the dart into the sleeve the snap ringis compressed by the ring 13 into its recess,

thus permitting the bevel 14 on the dart to abut the ring bevel 13b.However, when the dart is pulled upward through the sleeve, sufficientresistance is provided by the flat under surface of the ring to effectupward sliding of the sleeve before the ring 20 is compressed. Once thesleeve is topped against the upper stop 11, the snap ring can then becompressed by upward tugging and the dart withdrawn from the sleeve.Alternatively, a tensioned spring can be placed beneath the sleeve inthe recess so that it is automatically moved upward once the dart' isremoved.

Using an arrangement as shown in FIG. 4, the sleeve can be lowered againto cover the channels by bumping it downward with a weight on a wireline.

Since one object of the present invention is restore adequaterecirculation to a well hole without any substantial change in thepressure required to pump the drilling fluid, the body section 4 of thetool can be provided with at least one channel in the wall of the bodywhich, preferably, has an open area at least equivalent to the totalopen area of the fluid discharge orifices of any other member of thestring carried below it, e. g. a drilling bit. However, more than onechannel can be employed to accomplish this effect, and one or morechannels can be equipped with threaded, replaceable nozzles 21 so thatin any event the open area of the channels can be set to equal that ofthe bit orifices. Naturally, when more than one channel 7 is employed,as is shown in the drawing, the inlet of each from the passageway 6should be located so as to be covered over when the sleeve is in thenormal position, and each should be uncoverable when the sleeve isshifted to restore circulation to the bore hole.

FIG. 1 represents a case where the tool 1 is located in the drill stringjust above a drilling bit. Thus arranged, circulation can be restored tothe well hole at a point very near its bottom, but it will be understoodthat the tool can be located still higher up in the hole, e. g. asrepresented by FIG. 4 wherein a coupling 22 on a drilling pipe isthreaded onto the lower end of the tool instead of a drilling bit.

In FIGS. 1 and 4, the sleeve 9 is shown held in a preset position overthe channels 7 by frictional means, i. e. O-rings. FIG. 5 illustratesuse of a tensioned spring to hold the sleeve in the preset position.Using such an arrangement, the sleeve is held up by spring 23 untildisplaced by the dart 12. With the dart in place the sleeve can be helddown and channels 7 kept open until the dart is removed with a wireline.

It will be appreciated that devices other than a sleeve could beemployed as a covering member which could be previously set over thechannels 7 and later operated by an action taken at the surface touncover the members, e. g. valves can be installed which automaticallyopen when pumping pressure is raised above a certain level. In addition,obstructing members other than a dart or plunger could be used forshutting off flow of fluid through the passageway below the channels,e.g. a normally unseated disc or valve associated with the sleeve whichis moved to an open or closed condition depending upon the position ofthe sleeve in the passageway.

Although the present invention has been described with reference tospecific apparatus components and arrangements thereof, it willnonetheless be understood that still other embodiments will becomeapparent which are within the spirit and scope of the invention definedin the following claims.

Therefore what is claimed is:

1. A well drilling tool comprising:

a. a tubular body section having threads at each end which areconnectible to members of a drilling string,

b. a longitudinal passageway through the body section,

0. a channel which extends through the side wall of the body sectionfrom the passageway therein to the outside, and

d. a previously set operable sleeve member inside the body section whichnormally covers the channel through the wall of the body section andwhich uncovers the channel when operated, said sleeve member beingcontiguous with the wall of the passageway in the body section, andslidable in the passageway over and beyond the opening of the channel, I

e. an integral ring member which projects from the I gravity actuatedinto the sleeve.

4. Apparatus as in claim 1 and further comprising means for retrievingthe plunger by wire line.

5. Apparatus as in claim 1 wherein the channel in the wall of the bodysection has a removable nozzle inserted therein.

6. Apparatus as in claim 1 wherein said ring member also has a secondsurface for engaging said snap latch and whereupon withdrawing theemplaced plunger from said sleeve member the sleeve member first travelsupwardly and covers said channel and the snap latch is adapted fordisengagement from said ring member upon further upward movement of theplunger.

7. Apparatus as in claim 1 and further comprising at least one otherchannel which extends through the wall of the body section of the tool,said other channel being covered by the operable member when preset anduncovered upon operation of the member.

8. Apparatus as in claim 3 wherein at least one of the channels isprojected at an inclined angle with respect to the wall of the bodysection.

9. Apparatus as in claim 1 and further comprising a drilling stringhaving a central passageway for fluid affixed to one end of the bodysection of the tool.

10. Apparatus as in claim 9 and further comprising another component ofa drilling string attached to the other end of the body section of thetool, said other component having discharge orifices for fluid whichpasses through the string, and wherein the total open channel area is atleast equivalent to the total open area of the discharge orifices in theother component.

11. Apparatus as in claim 1 and including securing means for holding thesleeve in a normal position over the channel in the wall of the bodysection of the tool.

an axial direction.

1. A well drilling tool comprising: a. a tubular body section havingthreads at each end which are connectible to members of a drillingstring, b. a longitudinal passageway through the body section, c. achannel which extends through the side wall of the body section from thepassageway therein to the outside, and d. a previously set operablesleeve member inside the body section which normally covers the channelthrough the wall of the body section and which uncovers the channel whenoperated, said sleeve member being contiguous with the wall of thepassageway in the body section, and slidable in the passageway over andbeyond the opening of the channel, e. an integral ring member whichprojects from the inner surface of the sleeve, is axially alignedtherewith, and has a sealing surface which receives a matching sealingsurface on a flow obstructing plunger emplaced in the sleeve, andfurther comprising a snap latch which couples said plunger and said ringwhen the plunger is emplaced within said sleeve.
 2. Apparatus as inclaim 1 and further comprising a recess in the passageway of the bodysection of the tool and the sleeve is located in the recess. 3.Apparatus as in claim 1 wherein the plunger is gravity actuated into thesleeve.
 4. Apparatus as in claim 1 and further comprising means forretrieving the plunger by wire line.
 5. Apparatus as in claim 1 whereinthe channel in the wall of the body section has a removable nozzleinserted therein.
 6. Apparatus as in claim 1 wherein said ring memberalso has a second surface for engaging said snap latch and whereuponwithdrawing the emplaced plunger from said sleeve member the sleevemember first travels upwardly and covers said channel and the snap latchis adapted for disengagement from said ring member upon further upwardmovement of the plunger.
 7. Apparatus as in claim 1 and furthercomprising at least one other channel which extends through the wall ofthe body section of the tool, said other channel being covered by theoperable member when preset and uncovered upon operation of the member.8. Apparatus as in claim 3 wherein at least one of the channels isprojected at an inclined angle with respect to the wall of the bodysection.
 9. Apparatus as in claim 1 and further comprising a drillingstring having a central passageway for fluid affixed to one end of thebody section of the tool.
 10. Apparatus as in claim 9 and furthercomprising another component of a drilling string attached to the otherend of the body section of the tool, said other component havingdischarge orifices for fluid which passes through the string, andwherein the total open channel area is at least equivalent to the totalopen area of the discharge orifices in the other component. 11.Apparatus as in claim 1 and including securing means for holding thesleeve in a normal position over the channel in the wall of the bodysection of the tool.
 12. Apparatus as in claim 11 wherein the securingmeans comprises at least one O-ring fitted into a groove around theouter circumference of the sleeve.
 13. Apparatus as in Claim 11 whereinthe securing means is a tensioned spring which urges the sleeve in anaxial direction.